1. Field of the Invention
The present invention relates to an image processing method and apparatus, and particularly to combining sharp and blurred images of different resolution and exposure to produce a relatively high resolution, fully exposed and relatively sharp image.
2. Description of the Related Art
Two source images nominally of the same scene may be used to produce a single target image of better quality or higher resolution than either of the source images.
In super-resolution, multiple differently exposed lower resolution images can be combined to produce a single high resolution image of a scene, for example, see “High-Resolution Image Reconstruction from Multiple Differently Exposed Images”, Gunturk et al., IEEE Signal Processing Letters, Vol. 13, No. 4, April 2006; or “Optimizing and Learning for Super-resolution”, Lyndsey Pickup et al, BMVC 2006, 4-7 Sep. 2006, Edinburgh, UK, each being incorporated by reference. However, in super-resolution, blurring of the individual source images either because of camera or subject motion are usually not of concern before the combination of the source images.
U.S. Pat. No. 7,072,525, incorporated by reference, discloses adaptive filtering of a target version of an image that has been produced by processing an original version of the image to mitigate the effects of processing including adaptive gain noise, up-sampling artifacts or compression artifacts.
PCT Application No. PCT/EP2005/011011 and U.S. Ser. No. 10/985,657, incorporated by reference, discloses using information from one or more presumed-sharp short exposure time (SET) preview images to calculate a motion function for a fully exposed higher resolution main image to assist in the de-blurring of the main image.
Indeed many other documents, including US 2006/0187308, Suk Hwan Lim et al.; and “Image Deblurring with Blurred/Noisy Image Pairs”, Lu Yuan et al, SIGGRAPH07, Aug. 5-9, 2007, San Diego, Calif., incorporated by reference, are directed towards attempting to calculate a blur function in the main image using a second reference image before de-blurring the main image.
Other approaches, such as disclosed in US2006/0017837, incorporated by reference, have involved selecting information from two or more images, having varying exposure times, to reconstruct a target image where image information is selected from zones with high image details in SET images and from zones with low image details in longer exposure time images.
It is desired to provide an improved method of combining a sharp image and a blurred image of differing resolution and exposure to produce a relatively high resolution, fully exposed and relatively sharp image.